ISO 10928-2009 pdf free download

ISO 10928-2009 pdf free download.Plastics piping systems — Glassreinforced thermosetting plastics (GRP) pipes and fittings — Methods for regression analysis and their use
Systémes de canalisation en matléres plastiques — Tubes ef raccords plastiques thermodurcissables renforcés de verre (PRV) — Méthodes pour une analyse de rôgression et leurs utilisations.
A.1 Introduction
The design procedure described in this annex is used to formulate the minimum pressure performance requirements of GRP pipes made in accordance with the ISO system standards 10639171 and 10467 (4) The recommended minimum factors of safety relative to the products performance are given in these ISO system standards and are repeated in this annex.
NOTE The same procedures for pressure pipe design are used in CEN system standards, EN 1796 I and EN 14364(111
Like all plastics materials, GRP is subject to creep under applied loads. GRP pipe products are tested to establish the regression characteristics because they are influenced by the manufacturing method and the raw materials used.
This design procedure is based upon the principle that pipe products manufactured using a particular manufacturing process, product design and identified materials, wtien tested In accordance with a specified regression test method, e.g. ISO 7509 Fi, will exhibit similar regression characteristics. Test data derived from this test is analysed using method A of this International Standard. The slope of the mean regression line derived from this analysis represents the general regression characteristics of products made with similar materials and processes. For products made with similar materials and processes, the regression behaviour is essentially not dimension-sensitive, i.e. testing products of different diameters and thicknesses will give similar results.
The properties of GRP products, like all manufactured materials, are recognized as having an inherent variability, but it is assumed that the manufacturing facility will be operating a quality control system which will permit the determination of the coefficient of variation and AOL for the initial circumferential tensile strength.
A.2 Minimum factors of safety for long-term pressure requirements
Most GRP pressure pipes are installed underground and are subjected to stress due not only to internal pressure, but also to ring bending resulting from soil and traffic loads. Consideration of these combined loadings and examination of the effects of varying the values for the probability of failure at 50 years has indicated that the factor of safety for the combined loadings, i, shall be not less than 1,5.
Minimum ring deflection requirements are defined with respect to the pipe stiffness, which in effect defines the limits of the strain due to bending. Knowing the minimum acceptable value for ‘at arid the bending conditions. the minimum acceptable value for the factor of safety in tension q is calculated. Using these concepts, the ij values relating to the 97,5 % LCL and mean values have been calculated and are shown in Table A. 1.ISO 10928-2009 pdf free download.